1. Technical Field
The present disclosure relates generally to internal combustion engines. More specifically, the disclosure relates to operation of an internal combustion engine.
2. Background of the Invention
The volatile market for oil and oil distillates affects the cost of fuels to consumers. The increased costs may manifest as increased costs for kerosene, gasoline, and diesel. As demand and prices increase, consumers seek improved efficiency from their internal combustion engines. Engine efficiency, as it relates to fuel consumption, typically involves a comparison of the total chemical energy in the fuels, and the useful energy abstracted from the fuels in the form of kinetic energy. The most fundamental concept of engine efficiency is the thermodynamic limit for abstracting energy from the fuel defined by a thermodynamic cycle. The most comprehensive and economically important concept is the empirical fuel economy of the engine, for example miles per gallon in automotive applications.
Internal combustion engines, such as those found in automobiles, are engines in which fuel and an oxidant are mixed and combusted in a combustion chamber. Typically, these engines are four-stroke engines. The four-stroke cycle comprises an intake, compression, combustion, and exhaust strokes. The combustion reaction produces heat and pressurized gases that are permitted to expand. The expansion of the product gases acts on mechanical parts of the engine to produce useable work. The product gases have more available energy than the compressed fuel/oxidant mixture. Once available energy has been removed, the heat not converted to work is removed by a cooling system as waste heat.
Unburned fuel is vented from the engine during the exhaust stroke. In order to achieve nearly complete combustion, it is necessary to operate the engine near the stoichiometric ratio of fuel to oxidant. Although this reduces the amount of unburned fuel, it also increases emissions of certain regulated pollutants. These pollutants may be related to the poor mixture of the fuel and oxidant prior to introduction to combustion chamber. Further, operation near the stoichiometric ratio increases the risk of detonation. Detonation is a hazardous condition where the fuel auto-ignites in the engine prior to the completion of the combustion stroke. Detonation may lead to catastrophic engine failure. In order to avoid these situations, the engine is operated with an excess of fuel.
Accordingly, there is a need in the industry for improved methods of mixing fuel and oxidants prior to injection into internal combustion engines.